Home / 213.90-320.78-104.21

Finding the Fourth Proportional to 213.90, 320.78 and 104.21

Calculator

Solution

The fourth proportional to 213.90, 320.78 and 104.21 is: 156.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.90 : 320.78 = 104.21 : x
  2. Step 2: Convert to fraction form
    213.90/320.78 = 104.21/x
  3. Step 3: Cross multiply
    213.90x = 320.78 × 104.21
  4. Step 4: Simplify right side
    213.90x = 33,426.36
  5. Step 5: Solve for x
    x = 33,426.36/213.90
  6. Step 6: Final answer
    x = 156.27

Related Problems

Find fourth proportional to 106.95, 160.39 and 52.10
Half scale
Find fourth proportional to 427.80, 641.55 and 208.41
Double scale
Find fourth proportional to 214.90, 322.27 and 105.21
Similar ratio
Find fourth proportional to 320.85, 481.16 and 156.31
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.